A daily 180 microgram dose of vitamin K2 for three years was also associated with statistically significant improvement of vascular elasticity, according to findings published in Thrombosis and Haemostasis​​.

“This is the first study showing that long-term use of vitamin K2 in the form of MK-7 beneficially affects cardiovascular health,” ​said Cees Vermeer, Chief Innovation Officer at the R&D Group VitaK of the Maastricht University Holding (The Netherlands), and lead researcher on the study.

“The women taking the MenaQ7 vitamin K2 did not experience the typical age-related progression of arterial wall stiffening, and even made a statistically significant improvement of vascular elasticity, compared to the placebo group,” ​he added. “Our data demonstrated that a nutritional dose of vitamin K2 in fact improves cardiovascular outcomes.”​

K forms​

There are two main forms of vitamin K: phylloquinone, also known as phytonadione, (vitamin K1) which is found in green leafy vegetables such as lettuce, broccoli and spinach, and makes up about 90% of the vitamin K in a typical Western diet; and menaquinones (vitamins K2), which make up about 10% of Western vitamin K consumption and can be synthesized in the gut by microflora.

Menaquinones (MK-n: with the n determined by the number of prenyl side chains) can also be found in the diet; MK-4 can be found in animal meat, MK-7, MK-8, and MK-9 are found in fermented food products like cheese, and natto is a rich source of MK-7.

Study details​

Dr Vermeer and his co-workers recruited 244 healthy post-menopausal women and randomly assigned them to receive daily vitamin K2 supplements (180 micrograms per day, MenaQ7) or placebo for three years. Cardiovascular effects were assessed using pulse wave velocity and ultrasound techniques.

Data from the 227 women who completed the trial indicated that MK-7 supplementation led to significant decreases in both pulse wave velocity and stiffness measures. A beneficial effect was also observed in the elastic properties of the carotid artery for women with higher stiffness measures at the start of the study.

The researchers also looked at levels of desphospho-uncarboxylated matrix Gla-protein (dp-ucMGP), a marker of vitamin K status and reported risk factor for vascular stiffening. Three years of MK-7 supplementation resulted in 50% reductions in dp-ucMGP, compared to placebo. These effects were seen during the first year of the study and maintained for the next two years. No changes to markers of inflammation or markers of endothelial dysfunction, they added.

Heart and bone health​

The same cohort was examined in another study published in Osteoporosis International​​ in 2013 that supported MK-7’s bone benefits.

“Both studies are significant because they are long-term – three years of participation and then examination of the results,” ​said Hogne Vik, CEO of NattoPharma. “Observing changes in heart health, and bone health for that matter, take time. Our patience and perseverance has paid off with a study accepted by a highly prestigious medical journal that proves what we have known all along: that MenaQ7 Vitamin K2 truly delivers benefits for hearts and bones.”​

“Vitamin K2 ensures calcium binds to the bone mineral matrix and stays out of the arteries,” ​explained Dennis Goodman, MD, board-certified cardiologist and Director of Integrative Medicine at NYU Langone Medical Center in New York. “This is important because if calcium accumulates in the arteries, it may cause stiffness and blockages that can lead to serious cardiovascular events, such as heart disease and strokes.​

“This vitamin K2/MenaQ7 study, which is actually showing an improvement in arterial function, has the potential to dramatically impact the way we view prevention when it comes to cardiovascular health,” ​added Goodman. “Further clinical studies will be important to confirm these exciting findings.”​